1. Field of the Invention
The present invention relates to a multiband antenna, and more particularly, to a multiband shorted monopole antenna with a coupling feed.
2. Description of the Related Art
Recently, various kinds of wireless communication applications have emerged with the development and improvement of wireless communication technologies, such as notebook computers combined with wireless communication capabilities. Now notebook computers are mostly equipped with wireless local area network (WLAN) connection capabilities; however, in order to provide greater functionality, new notebook computers must provide antennas having multiband compatibilities to work with wireless applications such as wireless wide area network (WWAN) and world interoperability for microwave access (WiMAX). The WLAN antennas used in prior-art notebook computers are mostly inverted-F antennas, which bring challenges to engineers because of their size. In the prior art technique, such as that disclosed in the Taiwan patent no. 1293215 titled “Dual-Band Inverted-F Antenna”, which discloses a dual-band antenna using dual resonant paths to achieve dual frequency band operations, the antenna is only suitable for WLAN operation; due to its large size, it is usually difficult to apply such an antenna to fit in a mobile communication device for WLAN/WMAX dual-network or multiband operation. Therefore, in view of the deficiencies of prior-art techniques, it is necessary to provide a multiband antenna suitable for mobile communication devices.